/*
 * Copyright 2021 Shulie Technology, Co.Ltd
 * Email: shulie@shulie.io
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package io.shulie.surge.data.runtime.disruptor;

/**
 * Busy Spin strategy that uses a busy spin loop for {@link com.lmax.disruptor.EventProcessor}s waiting on a barrier.
 *
 * This strategy will use CPU resource to avoid syscalls which can introduce latency jitter.  It is best
 * used when threads can be bound to specific CPU cores.
 */
public final class BusySpinWaitStrategy implements WaitStrategy
{
	@Override
	public long waitFor(final long sequence, Sequence cursor, final Sequence dependentSequence,
			final SequenceBarrier barrier)
			throws AlertException, InterruptedException
	{
		long availableSequence;

		while ((availableSequence = dependentSequence.get()) < sequence)
		{
			barrier.checkAlert();
		}

		return availableSequence;
	}

	@Override
	public void signalAllWhenBlocking()
	{
	}
}
